The invention relates to a fan assembly, and in particular to a fan assembly and fan frame thereof.
Electronic devices generally produce heat during operation, and thus a demand exists for effective heat-dissipation devices. If a heat-dissipation device cannot effectively dissipate excess heat generated by the electronic device, performance can suffer, and more seriously, the electronic device may be burned out at high temperature. Moreover, since the number of transistors per unit area in an electronic device increases to improve performance, available internal space is reduced, and high temperature is concentrated therein such that performance deteriorates. Thus, an effective heat-dissipation device is an important component in micro-electronic devices such as integrated circuits (ICs).
The most popular heat-dissipation system is fan assembly. A fan assembly comprises a fan frame, hub, blades and motor. As shown in FIGS. 1A and 1B, conventional fan frames 11a and 11b are connected to motor bases 12a and 12b via a plurality of ribs 13a and 13b, respectively. The ribs 13a and 13b support the motor bases 12a and 12b. The ribs 13a and 13b can be cylindrical, curved, or streamlined. For example, the cross section of the rib 13a along line A-A of FIG. 1A is triangular, as shown in FIG. 1A-1; the cross section of the rib 13b along line B-B of FIG. 1B is circular, as shown in FIG. 1B-1, or is rectangular, as shown in FIG. 1B-2. Regardless of the shape of rib cross section, however, the ribs 13a and 13b have an identical linear shape extending from the motor bases 12a and 12b toward the fan frame 11a and 11b, respectively.
As shown in FIG. 1C, if the ribs 13 connected to the motor base 12 and the fan frame 11 are curved, the cross section thereof is not continuous. The side view of the rib 13, however, is fully shown in the figure for clear explanation of the fan frame 11a or 11b. The blades 14 of the fan 10 are radially arranged on an outer periphery of the hub 15 with a motor (not shown) disposed therein.
When the blades 14 rotate, since the ribs 13 with the same cross section extend linearly along the motor base 12 toward the fan frame 11, the lower edge of the blades 14 are parallel to the ribs 13. As the size of the fan assembly is reduced, noise is produced due to airflow resistance between the lower edge of the blades 14 and the ribs 13. Additionally, the noise level increases with the fan speed.